This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A128190 #5 Feb 18 2022 22:07:03 %S A128190 1,1,1,0,0,1,0,0,0,1,0,0,-1,0,1,0,0,1,-1,0,1,0,0,0,0,-1,0,1,0,0,-1,1, %T A128190 0,-1,0,1,0,0,1,0,0,0,-1,0,1,0,0,0,-1,1,0,0,-1,0,1 %N A128190 Inverse of A128189. %C A128190 Row sums = 1, 2, 1, 1, 0, 1, 0, 0, 1, 0, ... (the first 10 terms of A104162). %F A128190 Inverse of A128189 as an infinite lower triangular matrix. %e A128190 First few rows of the triangle: %e A128190 1; %e A128190 1, 1; %e A128190 0, 0, 1; %e A128190 0, 0, 0, 1; %e A128190 0, 0, -1, 0, 1; %e A128190 0, 0, 1, -1, 0, 1; %e A128190 ... %Y A128190 Cf. A104162, A128189. %K A128190 tabl,sign %O A128190 0,1 %A A128190 _Gary W. Adamson_, Feb 17 2007